Apparatus for forming juxtaposed coatings



Oct. 23, 1956 P. K. WEIMER ETAL APPARATUS FOR FORMING JUXTAPOSEDCOATINGS 3 Sheets-Sheet 1 Filed March 25, 1953 INVENTORJ 541/4 K.WE/Mf/B mm 4 A/ae C. THOMPSON QQZJM JTTORNEY I 23, 1956 P. K.IWEIMEREFI'AL 2,767,684

APPARATUS FOR FORMING JUXTAPOSED COATINGS v Filed March 25, 1953 3Sheets-Sheet 2 PA 11 A. wmf efiiifi HARE) C THOMPSON ll TTORNE 1 Oct.23, 1956 P. K. WEIMER ErA L APPARATUS \FOR FORMING JUXTAPOSED commas ssheets-sheet 5 Filed March .25, 1953 INVENTORJ PAUL K. WE/M519, HARRYTHOMPSON v .TTORNEY APPARATUS FOR FORMING JUXTAPOSED COATINGS Paul K.Weimer and Harry 'C. Thompson, Princeton, N. .L, assignors to RadioCorporation of America, a corporation of Delaware Application March 25;1953, Serial No. 344,499

10 Claims. (Cl. 118-503) This invention relates to apparatus for makingfine juxtaposed lines or strips as well as superimposed layers ofdifierent materials particularly useful .in making ray sensitive targetsfor cathode ray color television'tubes. More particularly this inventionrelates to apparatus for forming juxtaposed layers of a given width andsuperimposed layers of a ditferent width such as may form the colorfilter strips and signal strips of a target especially useful in asimultaneous color television pickup tube.

In the application of P. K. Weimer, Serial No. 344,498, now PatentNumber 2,745,773 filed simultaneously herewith and assigned to theassignee of this application there is shown and described apparatus forforming a plurality of juxtaposed color filter strips on a lightpermeable workpiece; each of the color filter strips being composed of aplurality of superimposed layers. A plurality of spaced signal stripsare positioned one on each of the color filter strips. The problems offorming such strips or layers will be more readily appreciated when it.is understood that they are extremely narrow in width ranging around afew mils or less. Such strips and layers are required to be accuratelylocated or registered with respect to each other; with the permissibletolerance being a few 10,000ths of an inch or less. When superimposedlayers are formed of different width it is necessary that the maskhaving elements, such as a wire masking grill, defining the width of theapertures and thereby the width of the strips or layers formed, bechanged to one having the same number of elements or wires but ofdiiferent thickness or diameter to secure the change in width ofsuccessive coatings. While it may be possible to form such matching setsof masking grills with that degree of precision required here, we havefound that the necessity for doing so may be avoided.

It is therefore a principle object of our invention to provide animproved apparatus for readily making fine juxtaposed coatings on aworkpiece with a high degree of precision.

Another object is to provide improved apparatus for readily making finejuxtaposed strips and strips superimposed thereon capable of a highdegree of precision in operation.

Another object is to provide apparatus for readily making finejuxtaposed coatings on a workpiece in which the elements forming theapertures in a mask are accurately closely spaced from the workpiece.

Yet another object is to provide an apparatus for forming juxtaposedstrips of a given width and superimposed thereon strips of a differentwidth and at the same time insuring great accuracy.

A further object is to provide an apparatus for making extremely fineand accurately located juxtaposed strips and strips superimposed thereonwherein the width of the superimposed layers may be readily varied andat the same time readily accurately registered in a predeterminedlocation.

In accordance with our invention we provide precision States Patentholder 19 movably mounted there-in.

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spacing means adjustably mounted on a framework which carries aworkpiece holder. The framework is removably mounted on a base whichsupports the masks forming the apertures through which material isevaporated onto the workpiece. One of the masks is made up of aplurality of fine closely spaced wires. The precision locating means areso positioned on the framework that they engage the individual wires ofthe wire masking grill and automatically space them with respect to eachother as well as the workpiece. Thus, in forming successive superimposedlayers on the workpiece, the framework supporting the workpiece mayreadily be disconnected from the base and removed therefrom. When theframework is once again connected to the base registration of givenportions of the workpiece with the same apertures of the wire maskinggrill is readily accomplished; registration being virtuallyautomatically accomplished when the precision locating means engages thewires of the masking grill. The holder may be mounted so as to bereadily displaced in a given direction to expose different portions ofthe workpiece to the apertures of the wire masking grill. A movable maskmay be mounted on the base having apertures which determine theeffective length of the apertures formed by the wire masking grill. Acontrolled atmosphere may be provided in a chamber in which theapparatus is mounted and the various movements of the workpiece andmovable mask are effected by controls mounted externally of the chamber;thus facilitating the successive formation of coating or strips ondifierent portions of the workpiece.

Further objects as well as advantages of our invention will be apparentfrom the following description and the accompanying drawing in whichFigure l is an elevational view, partly in section, of apparatusconstructed in accordance with our invention;

Figure 2 is a perspective view partially broken away for convenience ofillustration of a jig constructed in accordance with our invention;

Figure 3 is a sectional view taken along the line 33 of Figure 2;

Figure 4 is a sectional view taken along the line 4-4 of Figure 2; and

Figure 5 .is a fragmentary view on an enlarged scale of a portion of theapparatus shown in Figure 4.

Referring now to the drawing in detail it is seen that the apparatusincludes a jig 10 supported in a bell 11 above an evaporator 12; theinterior of hell 11, in the present instance, being connected to avacuum pump (not shown). Such an apparatus is described in detail in theP. K. Weimer patent referred to hereinabove. Only so much thereof as isdeemed necessary to a proper understanding of our present invention willbe repeated here.

Jig 10 is supported on a platform 13 having an opening 14 formedtherethrough. Jig 10 comprises two major subassemblies which are readilydisconnected and connected again .in accurately alined relation. Thebase or mask subassembly includes a fixed mask 15 having elementsdefining a plurality of apertures therebetween mounted on a base 17. Amovably mounted mask 16 is also mounted on base 17. The workpiecesubassembly includes a supporting framework 18 having workpiece ratelylocating workpiece holder 19 with respect to masks 15 and 16 areprovided.

On the upwardly presented surface of the base 17, a pair of oppositelydisposed guide rails 20, 21 form a guideway in which movable mask 16 isslideably mounted.

Movable mask 16 is advantageously provided when it is desired to eitherlimit the portion of the workpiece exposed to the apertures of fixedmask 15 or to oifset successively formed strips. Means for positioningmovable mask 16 with a high degree of accuracy are pro- Means foraccuvidcd by means of which both a large and fine adjustment of movablemask 16 may be readily made. Movable mask 16 may be selectivelypositioned in the guideway on base 17 by rotatably mounted arm 22, afinger portion 22' of which engages movable mask 16. Arm 22 is supportedon and rotatable with. rod 23. In the present instance a separate fineadjustment of movable mask 16 is effected by means of rod 24 rotatablymounted in base 17. Stops in the form of collars 25, 26 are mounted inspaced relation on rod 24 and are engaged by a downwardly projectingportion of movable mask 16.

Mounted on base 17 and positioned over movable mask 16 is the fixed mask15. One advantageous form of fixed mask is a wire masking grill having aplurality of fine closely spaced wires roughly indicated at 27 andsupported by two spaced cylinders 28, 29 which. may be threaded toreceive the .wire. The wire utilized may be of any suitable material.However, wire which may be stretched under tension such as Wire formedof an alloy of 85% nickel and 15% chromium is particularly suitable. Thewire is wound and then fixed on cylinders 28, 29 in any convenientmanner such as is well known in the grid making art; unwanted portionsof the wires being cut away. Cylinders 28, 29 and, with wires 27connected therebetween, are each mounted on a frame 30 as by bolts 31 insuch manner that wires 27 may be tensioned andstretched. This serves toremove kinks or bends remaining in the wires after their attachment tothe. cylinders.

As indicated above, workpiece holder 19 is mounted in framework 18. Anaperture is. provided in holder 19 in which workpiece 32 is removablyseated. Resilient finger 33 together with spring loaded plungers (notshown) firmly maintain workpiece 32 in position. Holder 19 is mounted ina guideway formed in framework 18 and is slidcable in the directionindicated by arrow 34. A spring loaded plunger (not shown) is mounted inframework 18 so as to bear against one end of the holder 19 and urge theopposite end thereof against one end of micrometer screw 35. Micrometerscrew 35 i is in threaded engagement with framework 18 by means of aprecision thread which permits fine adjustment of the position of theworkpiece holder. Rotatably mounted rod 36 is connected to micrometerscrew 35 through a suitable gear train. Graduated scales shown in Figure.2 are mounted on micrometer screw 35 and framework 18.

As described in detail in the above identified patent, set screws 50opposed by spring loaded plungers (not shown) may be mounted inframework 18 so as to permit the adjustment of the position of theworkpiece holder 19 in its guideway.

Means for securing accurate spaced relationship between workpiece 32,supported in holder 19 with respect to the wires of fixed mask 15, aswell as between the wires themselves are provided and include membershaving matching grooves or slots accurately formed there in to receivethe elements of fixed mask 15. Such members may advantageously be in theform of cylinders 38 and 39 with each threaded on its surface in anextremely precise manner so as to form a precision thread with thethreads on the cylinders matching one another. Methods of forming suchprecision grooves or threads of extreme accuracy are known in the metalworking art and need not be described in detail here. The threads areformed with the same number of turns per inch as there are elements perinch in wire masking grill 15. Cylinders 38, 39 are each removablymounted in a yoke 40 which in turn is adjustably connected to andsupported by framework 18. Two setscrews 41 are each threaded intoframework 18 and bear against the upwardly presented surface of yoke 40adjacent to each end thereof. A pair of bolts 42 are threaded throughframework 18 and into yoke 48 substantially at the midpoint thereof.Adjustment of bolts 42 permits rotation of yoke 40 and its cylinder asindicated by arrow 43 (Figure 3). Ad-

justment of set screws 41 permits rotation of yoke 40 and cylinder 38 inthe direction of arrow 44 (Figure 4). Furthermore, these adjustmentspermit vertical adjustment with respect to the workpiece. As shown mostclearly in Figures 4 and 5 in connection with cylinder 38, each cylinderis supported in its yoke so as to engage wires 27. When framework 18 isbolted on base 17 the threaded cylinders 38, 39 each engage the wires 27on opposite sides of workpiece 32. The threads serve to accurately spacewires 27 with respect to each other and also establish a pre-determinedspacing between wires 27 and the surface of workpiece 19 exposed to theapertures of the mask. Thus, framework 18 may be removed from base 17and, so long as workpiece holder 19 and workpiece 32 supported thereinare not disturbed, precise registration of the apertures with theportions of the workpiece previously exposed to the apertures isassured. Where strips of different width are formed, as in the case ofsuperimposed layers of different width, it is convenient to replace wiremasking grill 15 having wires 27 of a given diameter with a maskinggrill having the same number of wires per inch but of a differentdiameter. Now even though mask 15 has been replaced by a substitute maskformed of wires of dilferent diameter, proper precise registrationbetween the portions of the workpiece and the apertures between thewires is once again assured by the engagement of the wires with thealined threads of cylinders 38, 39. Furthermore, accurate uniformspacing between the wires is also attained.

Evaporator 12 is rotatably and adjustably mounted on platform 45 (Figure1). Heating element 46 is conveniently mounted so as to overhangcompartments for different materials formed in evaporator 12 and isenergized by means of leads 47 sealed through platform 45 as indicated.A flap 48 is rotatably mounted on a rod 49 so that it may be swung intoand out of position between evaporator 12 and jig 10.

The various movements of the movable parts within bell 11 may beeffected in any convenient manner. For example, as indicated in Figure 1each of the operating rods are connected through suitable gear trainsand rotatable seals through platform 45, to control knobs mountedoutside of bell 11. Such rotatable seals are well known and permitrotation of the rods which extend therethrough to effect the desiredmovement of the various parts within bell 11.

In operation a workpiece 32 is mounted in workpiece holder 19 andframework 18 is bolted to base 17. Movable mask 16 is adjusted to thedesired location and a first set of layers or strips is formed on theworkpiece by evaporating suitable material from evaporator 12. Theevaporated material passes up through the aperture or apertures ofmovable mask 16 and the apertures formed beween the wires of fixed mask15 to reach the exposed portions of workpiece 32. Other layers or stripsmay be formed intermediate those previously formed by stopping theevaporation of material by swinging flap 43 into posi' tion betweenworkpiece and the evaporator. Heating element 46 is turned off andwithout disturbing bell 11 adjustments are made to shift workpieceholder 19 as indicated by arrow 34. Now the portions of workpiece 32having the previously formed coatings thereon are in the shadows causedby the mask while other portions are now exposed to the apertures of themasks. In view of the engagement of the wires 27 with the threads ofprecision threaded cylinders 38, 39 all of the coatings thus formed areof uniform width. Furthermore the uniformity of the coatings formed isenhanced by the fact. that wires 27 are constrained by engagement withcylinders 38 and 39 to extend in a given plane accurately spaced fromthe workpiece. When it is desired to form another set of layers, as forexample a narrower layer, on those already formed framework 18 isunbolted from base 17. This may be readily accomplished withoutdisturbing the relationship between workpiece 32, workpiece holder 19,cylinders 38 and 39 and framework 18.

Fixed mask 18 is removed by unbolting frame 30 and a second mask in itssupporting frame is mounted in its place. The second mask has the samenumber of wires per inch as the first one but the diameter of the wiresis larger thereby defining apertures which are narrower than thoseformed by the first mask. Now framework 18 is once again bolted in placeon base 17 with the threads of cylinders 38 and 39 each engagingcorresponding wires of the second fixed mask. The proper spacing betweenthe wires of the fixed mask and the surface of workpiece 32 isautomatically insured. Furthermore, by their engagement with wires ofthe fixed mask, the threads on cylinders on 38 and 39 insure properspacing between the wires and also registration of the apertures betweenthe wires with respective portions of the surface of workpiece 32.

From the foregoing it is apparent that we have provided an improvedapparatus for precisely forming coatings or strips which are arranged inaccurate relation on a workpiece. Such an apparatus is particularlyuseful in forming the target of a pickup tube for producing simultaneouscolor video signals such as are described in another application of P.K. Weimer, Serial No. 344,497, filed simultaneously herewith andassigned to the assignee of this application. Such targets may includeextremely narrow filter strips with conductive signal stripssuperimposed one on each of the color filter strips. The various stripsare extremely narrow for example the color filter strips may beapproximately .002 inch wide while the signal strips may each beapproximately .0015 inch wide. In forming such superimposed strips it isnecessary that each signal strip extend along only one filter strip andbe centered thereon to avoid among other things short circuiting betweenadjacent signal strips and improper color rendition. Our apparatus notonly insures a high degree of uniformity between successively formedadjacent strips but also makes possible ready registration of thesuperimposed strips on those previously formed.

While we have described our invention in connection with the apparatusshown it is believed that obvious changes and variations may be madetherein without departing from our invention. It is, therefor, intendedthat all such changes and variations as come within the scope of theappended claims be included within our invention.

What is claimed is:

1. In an apparatus for depositing material in accurate relation on asurface of a workpiece, a base, a framework for supporting saidworkpiece and removably connected to said base, at least one mask onsaid base and including a plurality of elongated elements definingelongated apertures through which material may travel to portions ofsaid surface, and means connected to said framework and engaging each ofsaid elements and accurately locating said elements with respect to saidworkpiece.

2. In an apparatus for depositing material on a surface of a workpiecefor forming layers in accurate relation thereon, a base, means removablysupported on said base for supporting a workpiece, a plurality offlexible elongated elements supported in spaced relation on said baseand forming a plurality of elongated apertures through which thematerial may travel to said workpiece, and grooved means connected tosaid removable means and engaging each of said elements and accuratelypositioning said elements with respect to said workpiece.

3. In an apparatus for depositing material on a surface of a workpiecefor forming layers in accurate relation thereon, a base, a framework forsupporting said workpiece and removably connected to said base, a wiremasking grill including a plurality of wires supported on said base andconnected thereto, and means connected to said framework and removabletherewith engaging the wires of said grill and positioning the same.

4. In an apparatus for coating layers in accurate relation on a surfaceof a workpiece, a base, a framework for supporting said workpiece andremovably connected to said base, a wire masking grill supported on saidbase and connected thereto, said wire masking grill including aplurality of wires, and threaded means connected to and removable withsaid framework, the threads of said threaded means engaging the wires ofsaid grill and positioning the same.

5. Apparatus for mounting a workpiece in accurate spaced relation withthe apertures of a mask, comprising a base, a mask connected to saidbase, a plurality of spaced elements on said mask and defining aplurality of apertures therebetween, a framework for supporting saidworkpiece and removably connected to said base, a pair of membersconnected to said framework and removable therewith, said members eachhaving a plurality of grooves formed in the surface thereof with thegrooves in one member alined with the grooves in the other member, therebeing a groove on each of said members for each of the elements of saidmask, and said elements each being seated in said alined grooves.

6. Apparatus for mounting a workpiece in accurate spaced relation withthe apertures of a mask, comprising a base, a wire masking grillconnected to said base, a plurality of wires included in said wiremasking grill, a framework for supporting said workpiece and removablyconnected to said base, a pair of members connected to said frameworkand removable therewith, said members each having a plurality of groovesformed in the surface thereof with the grooves in one member alined withthe grooves in the other member, there being a groove on each of saidmembers for each of the wires of said masking grill, and said wires eachbeing seated in said alined grooves.

7. Apparatus for mounting a workpiece in accurate spaced relation withthe apertures of a mask, comprising a base, a wire masking grillconnected to said base, the wires of said grill defining a plurality ofapertures therebetween, a framework removably connected to said base forsupporting a workpiece, a pair of members each having accurately spacedthreads formed on the surface thereof and with the threads of one alinedwith the other, means adjustably supporting said members on saidframework in spaced relation, and each of said wires being engaged bythe alined threads and positioned in accurate spaced relation.

8. Apparatus for mounting a workpiece in accurate spaced relation withthe apertures of a mask, comprising a base, a wire masking grillconnected to said base with the wires thereof defining a plurality ofapertures, a framework removably connected to said base, a workpieceholder for supporting a workpiece in a given position and supported onsaid framework, a pair of members one on each of the opposite sides ofsaid holder and each having a plurality of alined grooves formed in thesurface thereof, there being a groove in each of said members for eachof said wires, and each of said wires being seated in alined grooves ofsaid members with the surfaces forming said grooves maintaining saidwires in accurate spaced relation one with the other and with saidholder.

9. In an apparatus for successively forming juxtaposed as well assuperimposed layers in accurate relation on a workpiece, a base, a pairof support members connected to said base, a plurality of spaced apartwires connected to said support members and supported thereby, saidwires defining a plurality of apertures therebetween, a frameworkremovably connected to said base and having a guideway formed therein, aholder slideably mounted in said guideway and for supporting aworkpiece, means for maintaining said holder in a given position on saidguideway, a pair of locating members one on each of the opposite sidesof said holder and adjustably connected to said framework in accuratespaced relation with said holder, said locating members each having aplurality of grooves formed therein one for each of said wires, thegrooves of one of said locating members being alined with thecorresponding grooves of the other, and each of assess-t 7 said wiresbeing seated in the alined grooves of said locating members with thesurfaces forming said grooves maintaining said wires in accurate spacedrelation one with the other and with said holder.

10. In an apparatus for successively forming juxtaposed as well assuperimposed layers in accurate rela tion on a "workpiece, a base, apair of support members connected to said base, a plurality of spacedapart wires connected to said support members and supported thereby,said wires defining a plurality of apertures therebetween, said basehaving a guideway formed therein, a movable maskslideably mounted insaid guideway and having at least one aperture formed therein, aframework reniovably connected to said base and having a guideway formedtherein, a holder sl'ideably mounted in said guideway and for supportinga workpiece, means for main taining said holder in a given position inits guideway, means for registering the aperture of said movable maskwith given portions of said workpiece, a pair of locating ReferencesCited in the file of this patent UNITED STATES PATENTS 2,260,471 McLeodOct. 28, 1941 2,391,595 Richards et a1. Dec. 25, 1945 2,453,582 MorganNov. 9, 1948 2,507,958 Cassman May 16, 1950

